Summary for oxygen service pipe Discussion
Phosphating of CS pipe for oxygen service is questioned here, but the replies stress that the real issue is oxygen-system suitability, not the pickling bath itself. Ken Vlach asks what the oxygen application is, what cleanliness standard applies, whether the phosphate is internal or external, and whether anything will be applied over it. He notes that for liquid nitrogen, medical nitrogen, and semiconductor gas piping, carbon steel is generally unacceptable, so HCl pickling and phosphating are not the key concern. For medical oxygen service, he points to ASTM B819 and related oxygen-service standards such as ASME B31, ASTM G88, ASTM G93, and CGA G-4 series documents. Venkatesh CV adds that CGA G-4.4 and NFPA 51 should provide the needed guidance and mentions commercially available pickling solutions or pastes. The later question asks whether API 5L Gr B welded pipe can be used for oxygen at 40 kg/cm² in a steel plant yard line.
Q. Dear Sir,
Please suggest the correct procedure of pickling of CS seamless pipe. Presently we are using 33% HCl solution and than putting into Zinc-Phosphate solution.
Sridhar Sur
Steel – India
2007
A. What is the oxygen application? What material & cleanliness standards apply? Grade of steel? Phosphating both internal and external surfaces? Anything applied over the phosphate?
For applications such as liquid nitrogen, medical nitrogen and semiconductor gas piping, the HCl pickling & phosphating issues are irrelevant since carbon steel is unacceptable piping material.
For medical oxygen service, ASTM B819, ‘Standard Specification for Seamless Copper Tube for Medical Gas Systems’ applies in the USA and possibly Canada. Similar to ASTM B88, Type K, but requires specific internal cleanliness/residue limits, that tubes be capped or sealed to maintain these limits, and properly labeled by the manufacturer.
There are many specifications regarding oxygen service, including:
AFNOR BP E86-002 004-APR-01 Oxygen piping systems – Design, operation and maintenance [French]
ASME B31 Standards of Pressure Piping
ASME B31.3 (2002) Process Piping
ASTM D2512 Standard Test Method for Compatibility of Materials with Liquid Oxygen (Impact Sensitivity Threshold and Pass-Fail Techniques)
ASTM G88 Standard Guide for Designing Systems for Oxygen Service
ASTM G93 Standard Practice for Cleaning Methods and Cleanliness Levels for Material and Equipment Used in Oxygen-Enriched Environments
G-4 Oxygen [issued by the Compressed Gas Association]
CGA G-4.1 Cleaning Equipment for Oxygen Service
CGA G-4.3 Commodity Specification for Oxygen
CGA G-4.4 Oxygen Pipeline Systems (EIGA Doc 13/02)
MIL-DTL-24800
[⇦ this spec on DLA] CLEANING COMPOUND – AQUEOUS – OXYGEN SYSTEMS COMPONENTS
NFPA 51: Standard for the Design and Installation of Oxygen-Fuel Gas Systems for Welding, Cutting, and Allied Processes.
NFPA 53: Recommended Practice on Materials, Equipment and Systems Used in Oxygen-Enriched Atmospheres.
NFPA 99C [Ed. note: now superceded by NFPA MGHB18 Standard on Gas and Vacuum Systems
(US) 29 CFR § 1910.253 Oxygen-fuel gas welding and cutting.
(US) 49 CFR § 56.60-1 Acceptable materials and specifications
[allowable carbon steel piping includes seamless ASTM A106, seamless or welded ASTM A53
[affil. link] Types S, F, and E steel pipe (with restrictions) or welded ASTM A134, ASTM A135 or ASTM A139 (with restrictions).] Ken Vlach [deceased]
– Goleta, California
Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.
A. Dear Shridhar
CGA G-4.4 and NFPA 51 should give you the required answers. I gather this is for oxygen line to a steel plant. There are commercially available solutions or pastes for example from Avesta which you can use for pickling.
Venkatesh CV
– Muscat, Sultanate of Oman
May 17, 2008
Q. I want to know whether CS welded pipes API 5L GrB can be used safely for conveying oxygen gas at 40 kscg pressure. OR only CS seamless pipes are to be used. The application is for supplying gaseous oxygen for steel melt shop in a steel plant. Yard piping details: length ~2000 m; size DN350, DN500; sch. 40
Sudhakar Mysore Somashekar
steel plant – Vizag, Andhra Pradsh, India
April 25, 2013